This invention relates to a mode control system for a combination radio/tape player unit. More specifically, this invention relates to a relatively simple and inexpensive switching system and circuit therefor for automatic switching of a radio/tape player unit between a "radio" mode and a "tape" mode.
Combination radio/tape player units in general are known in the art. Such units commonly include appropriate electronic components for receiving and amplifying a broadcast radio signal having a selected frequency and for converting this received signal to an audio output played over one or more speakers. The unit also includes appropriate mechanical apparatus for receiving a supply of magnetic recording tape, typically carried in a cassette or eight-track housing or the like, and for transporting the recording tape past a magnetic pick-up head which converts information stored on the tape to electronic signals for amplification and playback as an audio output over the speakers. The radio/tape player unit includes a so-called mode selector switch operable to select the desired mode of operation of the unit, namely, a "radio" mode wherein the radio signal is played over the speakers or a "tape" mode wherein the information from the tape is played over the speakers.
When the radio/tape player unit is designed and constructed for use in a home environment or the like, the mode selector switch commonly comprises a manually operated switch located on the face of the unit. The mode of operation of the unit is thus easily selected according to the desires of the individual merely by adjustment of the position of the switch. When the tape player portion of the unit is operated in a fast-forward or reverse condition to rapidly advance or rewind the tape, an uninterrupted audio output can be maintained by manually returning the mode selector switch to a "radio" mode position.
However, a large number of radio/tape player units are designed and constructed in compact form for installation in vehicles. In these compact units, the mode selector switch is normally mounted inside the unit in a position for automatic movement from a "radio" mode setting to a "tape" mode setting whenever a cassette or similar tape-carrying housing is inserted into the unit. Similarly, the mode selector switch is automatically returned to the "radio" mode setting whenever the cassette is removed from the unit. In this manner, mode selection is automatic thereby enabling the driver of the vehicle to operate the radio/tape player unit without diverting his vision from the road to search for and adjust switches on the unit.
In operation of the radio/tape player unit, it is periodically necessary to operate the tape player portion of the unit in a fast-forward or reverse condition to rapidly advance or rewind the recording tape. In units designed for vehicles, however, the use of an automatic mode selector switch prohibits operation of the unit in a "radio" mode during the fast-forward or reverse operating condition, since the mode selector switch is not accessible for manual adjustment. Accordingly, in radio/tape player units of this type, an audio output is not possible for the duration of the fast-forward or reverse condition which, with modern cassettes carrying relatively long lengths of recording tape, can continue for a period of a few minutes.
It is desirable, therefore, to provide a mode control system in a radio/tape player unit particularly of the type for installation in a vehicle, wherein the system automatically switches the unit between "radio" and "tape" modes in response to insertion of a cassette or the like into the unit and wherein the system automatically returns the unit to a "radio" mode whenever the tape player portion of the unit is operated in a fast-forward of reverse condition. The present invention fulfulls this need.